As far as I remember this is not possible. If you check out the "Question: What's the highest resolution you've seen?" topic you will see another discusion about this. There are also some good ideas there as well._________________Allowed to live by the good graces of Deleted, Shh.

You could use javascript to determine the window size, and then have php (or any other scripting language) select the background from a series of differentiated resolutions of the same picture.

But really, one giant background? That's bad form _________________bi-chromaticism is the extraordinary belief that there exists only two options
each polar opposite to each other
where one is completely superior to the other.

kame - Yeah, I know. I'm trying to figure out what to resize the image to in order to be efficient, but I don't want users with minute resolutions to see some kind of ugly border on the background image._________________fight

q: won't this MANGLIFY the quality of the image if it's less-than-astronomical resolution?

a: gd isn't the best at resampling images, but it does the job.

drui, what does this background look like, can you post a pic?_________________bi-chromaticism is the extraordinary belief that there exists only two options
each polar opposite to each other
where one is completely superior to the other.

That image is too pretty to have text, and tables, and other stuff crawling all over it. Please, in the name of all that is good design practice, don't use that image. _________________bi-chromaticism is the extraordinary belief that there exists only two options
each polar opposite to each other
where one is completely superior to the other.

the answer to your question is that this is not possible in html+css. the only way to do this is with scripting. dro mentioned perl and gd. there's also php and imagemagick. i wouldn't do it though.

unfortunately the picture would not make a very good background image unless you manage to position it exactly. the fact that it ranges from bright to dark will make finding a good contrasting color for your text troublesome. the main point of interest is the ground and the sunset. as such it would make an excellent header or footer image if you crop out just that bottom quarter of the image. and if you used an <img> as your header or footer you could resize it and center it. it would also eliminate the need to mute the colors in order to make your text readable.